Single sheet feeder



June 19, 1962 J. c. LAWRENCE 3,039,768

SINGLE SHEET FEEDER Filed oct. 25, 1957 9 sheets-sheet 1 June 19, 1962.1. c. LAWRENCE 3,039,768

SINGLE SHEET FEEDER Filed oct. 25, 1957 9 sheets-sheet 2 v INVENToR. 'h'59 JAMEdLA/VegA/c June 19, 1962 J. c. LAWRENCE 3,039,768

SINGLE SHEET FEEDER Filed oct. 25, 1957 e sheets-sheet E LQ; d lINVENToR.

Jil/w55' d A W95/VUE June 19, 1962 J. c. LAWRENCE 3,039,768

SINGLE SHEET FEEDER Filed oct. 25, 1957 9 sheets-sheet 4 54 55 56 5 7 6INVENTOR.

JAMES C. LAWRENCE @gee/E. j@ WMEM ATTORNEYS June 19, 1962 J. c. LAWRENCE3,039,768

SINGLE SHEET FEEDER Filed 0G12. 25, 1957 9 Sheets-$11861', 5

l 1N V EN TOR.

June 19, 1962 J. c. LAWRENCE SINGLE SHEET FEEDER 9 Sheets-Sheet 6 FiledOct. 25, 1957 f, I V rg INVENToR. JAMES a AwEA/c' llune 19, 1962 J. C.LAWRENCE SINGLE SHEET FEEDER Filed Oct. 25, 1957 9 Sheets-Sheet 7 @MMIMlm June 19, 1962 1. C, LAWRENCE 3,639,768

June 19, 1962 J. c. LAWRENCE 3,039,768

SINGLE SHEET FEEDER Filed Oct. 25, 1957 9 Sheets-Sheet 9 L91357.26.

INVENTOR. i0/ JAMES c'. LA wea/@6 BY /24 @WAHI @m1 x, CAM

United States Patent O 3,939,763 SINGLE SHEET FEEDER James C. Lawrence,7911 th Ave. S., Seattle, Wash. Fied Get. 25, 1957, Ser. No. 692,440 10Claims. (Cl. 271-59) The present invention relates to 'a feeder lforfeeding to a machine, such as a sander, for example, single sheets, suchas of plywood, from a stack. This application is a continuation-impartof my application Serial No. 488,643 filed February 16, 1955, now U.S.Patent No. 2,921,788.

In general, the purpose of the feeder is to receive a stack of closelypiled sheets and automatically to feed these sheets edgewise, one at atime, from the top of the stack. An object of the invention is toprovide such a sheet feeder which can handle large sheets of material,such as four feet by eight feet, and which can be adjusted readily tofeed sheets of different width and length.

Another object is to provide a sheet feeder of automatic character whichwill receive -a stack of sheets Ifrom a conveyor when the feeder isempty and li-ft such sheet stack until the upper sheet reaches a feedingstation at a predetermined elevation, whereupon single sheets are fededgewise from the top of the stack in sequence, and the stack of sheetsis raised automatically, the thickness of one sheet between each sheetfeeding operation, until all the sheets of the stack have been fed. Whenthe feeder has thus been emptied, it will receive automatically anotherstack of sheets, and the sheets of this stack will he fed similarly insequence.

A particular object of the invention is to position each sheetaccurately before it is fed edgewise yfrom the stack, so that it will bealigned precisely in predetermined position before being fed, and thencewill be moved along -a true path into the machine. An associated objectis to enable alternate sheets to be fed lfrom the top of the stack oneodset in one direction and the next offset in the opposite direction apredetermined amount transversely of the direction of feed from acentral location. If the sheets are fed to a sander, for example, such afeeding technique will produce even wear on the sanding rolls of thesanding machine.

An additional `object is to provide suitable controls for such a sheetfeeder so that the feeder may be stopped and started at the will of theoperator, its speed of feed may :be regulated, and the type of sheetfeeding operation may be selected so that :alternate sheets -will beoffset to opposite sides of ya central position, as discussed above, orall the sheets will be fed from a central position, as may fbe desired.

The sheet `feeder includes an elevator onto which a stack of sheets tobe fed is delivered, and when in place upon the elevator it isautomatically hoisted. When the top of the stack carried by the elevatorreaches feeding elevation, the elevator movement automatically isstopped and automatically reciprocable squaring arms are moved to engagethe top sheet edgewise and shift it transversely of the feedingdirection as may be necessary to square the sheet with the feedingdirection. Sheet feeding means then slide the sheet lengthwise from thetop of the stack. As soon as this sheet has been moved substantially offthe stack, upward movement of the elevator is initiated again to raisethe stack a distance equal to the thickness of the sheet thus fed.Thereupon the squaring arms are reciprocated to square the new topsheet, and it in turn is slid olf the top of the stack by the sheetfeeding means. When all the sheets in the stack have thus been fed, theempty elevator vautomatically is lowered to receive another stack ofsheets.

Details of the preferred sheet feeder mechanism are shown in theaccompanying drawings and described here- 3,639,768 Patented .Func 19,1962 lCe after, but it will be appreciated that many of such details maybe altered within the scope of the invention.

FIGURE l is a perspective view of the sheet feeder with parts brokenaway.

FIGURE 2 is a transverse sectional view through a portion of the sheetfeeder taken on line 2 2 of FIG- URE 17, and FIGURE 3 is a similar viewshowing parts in a different operative position.

FIGURE 4 is a detail longitudinal sectional View through an operatingcylinder shown in FIGURES 2 and 3.

FIGURE 5 is `a detailed bottom perspective view of the squaring arms andtheir drive mechanism at the right end of FIGURES 2 and 3.

FIGURES 6 to 15, inclusive, are diagrammatic views of the squaring armdrive pistons shown in various positions.

FIGURE 16 is Ia vertical transverse section through the sheet feeder.

FIGURE 17 is a side elevation view of a portion of the upper part of thesheet feeder, and FIGURE 18 is a similar view with parts in a different`operative position.

FIGURE 19 is a vertical sectional View through brake mechanism of theapparatus.

FIGURE 20 is a diagrammatic perspective view of elevator drive mechanismand FIGURE 2l is an enlarged detail view of its hydraulic cylindercomponents.

FIGURE 22 is a wiring diagram of the control system.

FIGURE 23 is a top perspective view of an alternative type of sheetsquaring and feeding mechanism. v

FIGURE 24 is a longitudinal sectional view through the sheet squaringand feeding mechanism of FIGURE 23, showing parts in one operativeposition, and FIG- URE 25 is `a similar view with parts in a differentoperative position land having parts :broken away.

FIGURE 26 is an end elevation through such alternative mechanism takenon line 26-26 of FIGURE 24.

The general type of operation performed by the apparatus involvesreceiving edgewise a stack of panels piled in face-to-face contact,elevating such stack of panels until the upper panel has reached apredetermined feeding position, arresting upward movement of the stackat such location, sliding the uppermost panel edgewise olf the top ofthe stack in a feeding operation, raising the stack through `a furtherincrement equal to the thickness of the panel discharged, slidinganother panel oft' the top of the stack in a feeding operation, againraising the stack through :an increment equal to the thickness of thepanel discharged, repeating the single panel feeding and incrementalstack raising operation until all the panels in the stack have thus beendischarged one by one, and then receiving into the .apparatus anotherstack 0f panels from which individual panels will -be fed in likemanner.

The feeding mechanism designed to accomplish this operation is shown-generally in FIGURES l and 16. A stack of panels S, the panels of whichare to be fed individually, is moved edgewise into the apparatuspreferably on rolls 1 from a suitable conveyor which is not shown. Theserolls are located alongside the lframe 10 of the apparatus, which is ofgenerally rectangular shape. Within such frame and coplanar with rolls 1are rolls 11 of `another roll set. The rolls 1 and 11 are driven all `atthe same speed by a motor 12 with a suitable gear reduction drive, sothat the drive chain 13 interconnecting the rolls and powered by themotor 12 will move rather slowly. The machine frame includes fourcolumns 14 located one at each corner of the lower portion of Vframe 10,and these columns carry a superstructure 15 bridging between thecolumns.

Within the frame is received an elevator including two parallel endmembers 16 and parallel bars 17 interconnecting such cross members 16and spaced apart distances equal to the spacing of -rolls 11 so thatwhen the elevator platform is in its lower position the bars 17 arelocated in alternate arrangement with the rolls 11. Elevator hoistingchains 2 in housings Ztl, one at each corner of -the frame alongside acolumn 14, are connected to the ends of the elevator platform bars 16forming the corners of such platform. The hoisting chains 2 are drivenby chain and sprocket mechanism within housings 21 at `one side of theframe, and one of these chain drives in turn is driven by reversinggearing in housing 22. Movement of the hoisting chains 2 at one side ofthe frame is transmitted to the hoisting chains 2 at the other side ofthe frame by shafts 23 interconnecting the upper drive sprockets ofthese chains at opposite sides of the frame. v

The drive for the hoisting mechanism in housings 21 connected to chainsZ must, of course, be reversible, and the vertical movement of chains 2required is not great. Consequently, reversible drive of the hoistingchains may be' effected conveniently by a member reciprocatinghorizontally in the superstructure of the frame which will coordinatethe drive at opposite ends of the elevator. Conveniently thereciprocating member may be an elon- 'gated cylinder 24 guided by andmovable relative to a stationary piston on a rod 25 shown in FIGURE 2l.Chains 28 may be secured to the opposite ends of this cylinder, to thegearing mechanism 29 in casing 22 and to the chain drive at the oppositeend of lthe superstructure so that, as the cylinder 24 reciprocates, theshafts 23 will be rotated to move the chains 2. Reciprocation of suchcylinder 24 on rod 25 is effected by supplying fluid under pressure,such as oil, through the connection 26 to the left end of the cylinder24, as seen in FIGURE 1, for lowering the elevator. On the contrary,fluid under pressure can be supplied through connection 27 to shift thecylinder from the position shown in FIG- URE l to that of FIGURE 18 toraise the elevator.

Within the frame structure bounded .generally by columns 14 andsuspended yfrom the superstructure 15 is the individual sheet feedingmechanism. Such mechamsm of the type shown in FIGURES l to 3 and 16 to18 is supported from shafts 3 spanning the superstructure by parallellinkage arms 36 pivotally mounted by opposite ends of such shaftsrespectively. The swinging ends of arms 30 are interconnected by andcarry bars 31 disposed in parallel arrangement, as shown best in FIGURES2 `and 3, on which the various components of the feeding mechanism aremounted. These bars will be elevated bodily and will move endwiseslightly `as the arms 30 swing about the axes of shafts 3.

In opposite ends of the bars 31 are mounted axles 32 carrying sprockets33 about which extend two endless chains 34 arranged in parallelvertical planes. These chains are interconnected by sheet feeding pusherbars 35 shown best in FIGURES 2, 3, 16, 17 and 18. These chains extendlengthwise of the feeder frame a distance greater lthan the length ofthe longest panel to be fed by the apparatus, and in order to reduce asfar as possible the dwell between the feeding of successive panels, itis preferred that two of such bars 35 be provided.

In order that the feeder may be sumciently versatile to be used forfeeding machines operating at different speeds it is preferred that avariable speed drive be provided for the endless chains 34.Conveniently, such la variable speed drive may be effected by an oilmotor 36 the speed of which can be varied sunply by regulating thesupply of oil to the motor. This motor, `as sho-wn in FIGURES 2 and 3,will drive chain and sprocket mechanism 37 to turn one of the shafts 32carrying sprockets 33 with which the chains 34 lare engaged. As thesechains are driven the bars 35 will always move in the direction fromright to left, as seen in FIGURES 1, 2 and 3, when carried by the lowerstretches of the chains. Since bars 35 will not be thicker than thethinnest panel to be fed, such movement will cause each bar during such4 travel to slide only a single panel from the top of a stack on theelevator.

In feeding panels from the feeder to a machine `such as a sander, it isusually important that the panel is located accurately transversely ofthe direction of feed. Also, it is important that the panel be squarerelative to such machine and the pusher Ibars 35. Before engagement ofsuch a pusher bar with an edge of a panel, therefore, means are providedfor squaring the position of the top panel irrespective of theorientation of Ithe stack S of panels on the elevator. Such meansinclude pairs of oppositely reciprocable squaring arms shown best inFIG- URES 2, 3, 5 and 16. Each pair of such arms includes an arm 4having a blade 40 engageable with one edge of the top panel on a stackand an opposite arm 41 carrying a blade 42 engageable with the oppositeedge of the top panel.

Drive mechanism for the squaring arms 4 and 41 effects simultaneousreciprocation in opposite directions of both squaring arms in each pair.Such drive mechanism includes racks 43 and 44 on the squaring arms 4 and41, respectively, with which mesh gears 45 and 46, respectively.Rotatably integral with each gear 45 is a gear 47 and rotatably integralwith each gear 46 is a gear 43. Rotation of gears 45 and 46 will thus beeffected by gears 47 and 4S, respectively, and simultaneous rotation ofthese gears will eect simultaneous reciprocation of the squaring arms 4and 41, because of the engagement of gears 45 and 46 with the racks 43and 44. If the gears are rotated properly relative to each other, thesquaring arms can be thus moved simultaneously toward each other, and ifthe gears are rotated oppositely, the squaring arms will be movedsimultaneously to separate plates 4@ and 42.

Since, in order to square a panel of any appreciable length, it isdesirable to engage an edge at a plurality of spaced locations, thedrive mechanism is arranged to move the two squaring arms 4 and the twosquaring arms 41 shown in FIGURE 2, for example, simultaneously in thesame direction and to the same extent. Actually, it would be possible tosquare the position of a panel simply by engaging one edge with a singlesanering member and shiftino the panel edgewise until its opposite edgeengaged fixed locating stop means. Particularly for long panels,however, the squaring action can 'be effected more accurately andexpeditiously by engaging one edge at a plurality of locations.

Also, while as mentioned above a panel might be located by pushing itedgewise into engagement with fixed locating stop means, it isfrequently desirable to locate one panel in one edgewise position forfeeding and the next panel in a different edgewise location for feeding.Moreover, it is ordinarily desirable to locate panels of differentwidths in different positions for feeding. With the present type ofsquaring apparatus engageable with opposite edges of a panel at aplurality of locations, it is possible to locate alternate panels indifferent positions and to accommodate and feed panels of ditferentwidths quite readily. In order to obtain such an operation, however, itis necessary that all of the squaring arms be driven conjointly and inVrelated fashion.

To effect controlled reciprocation of the squaring arms and 41, it isonly necessary to coordinate the rotation of gears 47 and 48. Y

As shown in FlGURES 2 and 3, the gears 47 are driven conjointly becausethey mesh with the racks 5 and Sil, respectively, of drive bar 51.Similarly, the gears 45 mesh respectively with racks 52 and 53 of driverod 54. Reciprocation of drive rod 51 thus will effect simultaneous andequal reciprocation of squaring arms 4 in the same direction, andmovement of drive rod 54 will effect simultaneous and equal movement ofsquaring arms in the same direction. It is therefore only necessary tocoordinate the movement of drive rods 51 and 54 in order to establishdie initial positions and spacing of the squaring plates 40 and 42 whenopen and their closed positions depending upon the width of the sheet tobe squared and the location `of such sheet desired relative to themachine to which the sheet is to be fed.

The mechanism for reciprocating the drive rods is shown best in FIGURE-S2, 3 and 4 as incoiporating composite pistons and cylinders. Since thepiston and cylinder mechanism is the same for each of the drive rods, asshown in FIGURE 4, only one of these need be described. Eachcomposite'actuator includes an outer cylinder 55 in Which a piston 56reciprocates. This piston carries an inner cylinder 57 and has anaperture through which the drive rod may move. The drive rod in turn hason it a smaller piston 58 which can reciprocate in the inner cylinder57.

Fluid under pressure, such as air, is supplied to and exhausted from theouter cylinder 55 at one side of the piston 56 through a conduit 55',and such fluid is supplied to and removed from the outer cylinder at theother side of the piston 56 through a second conduit 55". Air or otherfluid under pressure is supplied to the inner cylinder 57 at one side ofpiston 58 by an aperture 57 communieating with a lbore in the drive rodand a conduit 57" connected to the bore. Fluid under pressure issupplied to and exhausted from the inner cylinder 57 at the oppositeside of piston 58 through an aperature 58', a bore in the drive rod `anda conduit 58 connected to it.

It will be appreciated that it would be very diicult to balance thepressures .in the two cylinders 55 for the two drive rods l51 and 54with precision, and similarly it would be difficult to balance exactlythe pressures in the cylinders 57 for the two drive rods. Suchpressures, therefore, cannot be relied upon to move the drive rods 51and 54, and consequently the squaring arms 4 and 41, to predeterminedsheet locating positions. For that reason positive stop mechanismcooperating with the drive rods l51 and 54 and operable to stop thempositively in predetermined operative positions is provided.

The drive rod stop mechanism as best shown in FIG- URE 5 includes ashaft 6 carrying pinions 60 and 61 which mesh respectively with theracks 62 and 63 on stop bars 64 and 65. These bars are suitably mountedalongside the respective paths of reciprocation of drive rods 51 and 54,in parallel, and such stop bars have hooked ends 66 and '67,respectively, which project into the paths of movement of theirrespective drive rods. When either of the drive rods strikes the hook ofits stop bar, the movement of such drive rod will be interrupted, andthe squaring plates 4d or 42 controlled -by such drive rod will bepositioned as positively as though such plates constituted stationarylocating stop means. When the squaring plates are thus located, they doactually constitute iixed reference stop means, and for that particularoperation serve the same function as stationary stop means.

In order to accommodate panels of different widths and in order to setthe stop bars for locating the squaring bars 64 and 65 is provided. Suchadjustment conjointly of the positions of both bars is effected byturning handle 68 to rotate shaft 6, which in turn moves the stop bars64 and 65 simultaneously in the same direction and to the same extent.Such stop bars may be held in any adjusted position by providing aspring-pressed pin in the handle of crank 68, which will engage in anyselected hole of the latch plate 69.

By suitable control mechanism fluid under pressure can be supplied toboth of the inner cylinders 57 and to one only of the outer cylinders55. By thus regulating the supply of fluid pressure to the cylinders andby setting the stop bars properly panels of any Width within limits canhe fed from the top of a stach successively along a ysinglepredetermined path, or panels fed from the top of the stack may be movedalternately along two offset paths. This latter type of operationfrequently is desirable when the panels are fed to sanding machines toreduce the wear on the sanding rolls. FIGURES 6 to l5, inclusive,illustrate diagrammatically positions of the stop bars which would beestablished to handle feeding of panels of different Widths, and eitheralong a single path or alternately along oset paths.

Assuming that air under pressure is supplied to the rig .t

i ends of both cylinders 57 and both cylinders 55 as seen in FIGURES 2and 3, the squaring arms would be moved into and held in the fullyextended positions shown iii FIGURE 16. In this position it is assumedthat the squaring plates 40 and 42 are spaced apart sixty inches.Because the gears 45 are twice as large as the gears 47 and the gears 46are twice as large as the gears 43, the squaring arms 4 and 41 Will bemoved twice as far as the drive rods 51 and 54. Since it is desired tobe able to feed with the feeder apparatus panels from twelve inches inwidth to forty-eight inches in width in increments of an inch, it isappropriate for the stroke of the pistons 58 in cylinders 57 to be threeinches and the stroke of the pistons 56 in cylinders 55 to be nineinches.

A sanding machine, for example, receiving panels from the feederdescribed, normally would be able to accommodate panels forty-eightinches in width. lf narrower panels are fed, it usually is desired tooifset them first in one direction and then in the other transversely oftheir lengths, so that one edge or the other of each panel will bealigned with the location which the edge of a fortyeight inch panelwould have occupied. Bearing in mind the maximum width opening of sixtyinches of the squaring plates 40 and 42, the strokes of the larvepistons 56 as being nine inches, tlie strokes or the small pistons 53relative to their cylinders 57 as being three inches, and the movementof the squaring arms 4 and 4l being twice as great as the movement ofthe drive rods 5l and 54, the following table shows the relationship ofpiston movement to squaring plate positioning for panels of differentWidths centered or alternately offset asrrepresented by theillustrations of FIGURES 16 and 6 to l5, respectively.

Panel Large Small Port Large Small Strbd Stop Fig. Width Position PortPort Stops Strbd Strbd Stops Spac- Piston Piston Shift Piston PistonShift ing 16 0l] 0H Oll Oll 0I] 0l] 0l! 60H 6 48 Centered.. 3 0 0 3 6"48 7 48]/ d0 3]/ 0l! 6l] 3l] 0l! 6l! 4g/l 8 42" Otlset 6 to Port.. 6 C"l2 0 3" 6" 42 9 42 Centered.. 4% O 9 4% 0 9 42 l() 36 Oiset 12" toPort.. 9 0 18" 0 3 6 35 ll 36" Centered.. 6" 0" l2 6 0 12 36 12 30 Oset18 to Port.. 9" 3 24" O 3 6 30 13 30" Centered.- 7% 0" 15 7% O l5 30 1424/ dO- gli 0N 18]/ gli 0N 18!! 2&1/ 15 A 18/1 d0 9H 1%!! 21H 9]/ 1;/ll21H 181/ plates either so that successive panels of a given Width willbe fed along the same path, or along alternately offset paths, mechanismfor adjusting the positions of the stop While the representations ofFIGURES 6 to l5 of the positioning of pistons 56 and 58 in cylinders 55and 57 are very diagrammatic, the showing in FIGURES 2 and 3 sheaves isa much more structural representation of the mechanisrn illustrating themovement of the squat-ing arms which occurs in positioning for offsetfeeding a panel thirty-six inches in width and corresponding to thediagrammatic representation of FIGURE 10. ln such offset squaring, asrepresented by this gure and by FIGURES o, 8 and l2, fluid underpressure is supplied to the left end of one of the large cylinders S andto the right end ofthe other through connection 55, the opposite endsbeing vented. As illustrated in these figures and in FIG- URES 2 and 3,such iluid under pressure is supplied to the left end of the portcylinder 55 and to the right end of the starboard cylinder 55 consideredin relation to the direction of panel feed.

ln .FGURE 2 air under pressure has been supplied to the left end of bothsmally cylinders 57, the right ends being vented. Piston 5b of drive rod5l has thus been moved fully to the right in its cylinder 57, while thelarge piston Se is held fully in its position to the left. This hascaused the squaring arms to be moved inward six inches from heirextended positions.

At the same time air under pressure supplied to the left end of thelargeport cylinder 55 is causing piston 56 to move to the right as seen inFIGURE 2, but althougi air also is supplied to the left end of the smallport cylinder 57, port piston 58 is not moved to the right relative toits cylinder because ofthe faster movement of the larger piston,although it is immaterial whether the smaller piston moves relative toits cylinder under these circumstances. In any event, such movement ofdrive rod 54, effected by movement of piston 56 acting on cylinder S7,has drawn the squaring rods el inwardly a distance of twelve inches intoengagement with the edge of the thirt six inch wide panel P. As the portpiston 56 continues to move from its position of FGURE 2 to its positionof EGURE 3, the squaring plates 42, Jullcd by their bars, will drag theupper panel l from centered position into the position offset six inchesfrom centered position which is shown in FiGURE 3.

Both the set of squaring plates 4G and the set of squaring plates 42will be stopped in their positions of FIG- URE 3. PlChe squaring plates49 will be stopped in the positions illustrated by bottoming of thestarboard piston S at the left end of its cylinder md of the smallstarboard piston 58 at the right `end of its cylinder 57. The positionsof squaring plates 42, will be established by the engagement or" driverod 54?- with the hook 65 of its stop bar 64. lf it were not for suchengagement, drive rod 54 would continue to move to the right beyond theposition shown in FGURE 3, because of the air pressure supplied to theleft end of cylinder S7 tending to move piston 58 to the right in suchcylinder. This piston will remain fully to the left in its cylinder,however, while piston 56 bottoms on the right end of its cylinder S5,because of the much larger surface area of piston Se on which the airpressure is acting.

The position of hook 65 of stop bar 64 engaged by drive rod S4 is shownin FIGURE 10, and in a similar manner the stop mechanism is set byadjustment of handle 68 to interrupt movement of the drive rods in theproper positions for the width or" the panels being fed and the type offeeding desired, i.e. whether centered or offset, in each instance. lfthe panels are to be fed in centered position, as illustrated by FEGURES7, 9, 11 and 13, the hooks of the two stop bars will, of course, in allthese instances be in alignment and abutted respectively by the ends ofthe drive rods.

Where a panel is to be offset to one side or the other from its centralposition, one drive rod will move farther than the other, as shown inFIGURES 8, and 12, as described above. Adjustment of the stop bars willstill be effected conjointly and to the same extent, as shown in thesegures. Consequently, the positions of the hooks 66 and 67 will be set tobe contacted by the one of the drive rods which moves farthest. Theother drive rod Y 8 will not be moved into engagement with its stop hookbecause iluid under pressure is not admitted to the left end. of thelarger cylinder 55'.

. When panels are to be fed in offset position, however, it is usuallypreferred that alternate panels be odset in. opposite directions,altaough the offsetting could always. be in the same direction. For onefeeding operation, therefore, as shown in FIGURES 8, 10 and 12, airwould besupplied to the left end of the large cylinder 55 for the driverod 54 and to the right end of cylinder 55 for the drive rod 5l, theopposite ends being vented, for the purpose of holding the starboardpiston 56 fully to the left as seen in those figures. On the nextoperation fluid under pressure would be supplied to the left end of thelarge cylinder 55 for the drive rod 51, so that piston 56 for that driverod would be moved while simultaneously fluid under pressure would besupplied to the right end of theA large cylinder 55 for drive rod 5d,thus preventing move-- ment of the piston S6 for drive rod 54. ln thisinstance, therefore, the drive rod S1 would engage its stop hook 67,whereas drive rod S4 would be moved only an amountv equal to the strokeof piston 58 in its cylinder 57. On the next operation the supply offluid under pressure would be reversed again so that drive rod 54 wouldmake the longer stroke and drive rod Sl would be moved only a relativelyshort distance, as shown in FGURES S, 10 and 12.

After the top panel of the stack has been squared in theA desiredposition for feeding, as described above, motor driving chains 34 movesa pusher bar 35 into engagement with a panel end to feed the panel.Motor 36 will have been regulated so as to feed the panel off the stackas rapidly as the machine to which the panel is fed can accommodate it.ln such feeding it is desirable that the bottom of the panel being fedbe disposed in a predetermined position relative to the machine to whichit is fed. The bottom of the panel being fed should, for example,usually be precisely level with the table of the machine to which thepanel is being fed or just slightly above it. The upper surface of thetop panel on the stack must, however, be below chains 34. Because thepanels to be fed may range from one-quarter of an inch to two inches inthickness, it is desirable to make the position of the panel feedmechanism adjustable vertically to accommodate panels of differentthicknesses.

As previously mentioned, the sheet feed mechanism bars 3l are mountedfor vertical movement on the swinging ends of arms 30. To locate thebars 3l and the chains 34 at the proper elevation to accommodate panelsof the thickness to be fed, therefore, it is only necessary to limit thedownward movement of the bars 3-1 at the proper position. Downwardmovement of the bars is thus limited by chains 36 attached to the bars3l preferably at their central portions, and extending upward over asupporting shaft 37 journaled on the upper portion of the framesuperstructure 15. The rotative position of shaft 37 may be altered byturning shaft 38 which is connected by chain and sprocket mechanism toshaft 37. Shaft 3S is turned by movement of handle 39 connected to it,and this handle may have a latch pin engageable in holes of the plate 39to hold the chains 6 at the desired elevation selected.

It will be evident that the chains 36 merely l'nnit downward movement ofbars 3l. If the elevator should lift a stack of panels so that the upperpanel engages and lifts chains 34 and these bars, the chains 36 will notprevent upward movement of the sheet feeding structure. Instead the arms3ft will simply be swung upward, and such movement will be cushioned bysuch upper panel assuming the weight of the superstructure. The arms llof one pair are formed as bell cranks having lateral extensions 7. Tothese extensions are connected tie members 70 extending into a casing 7iand secured to a piston fitted in the casing. Air under pressure may besupplied to the casing by a pipe '72, so that the weight of thesuperstructure on arms 3l) will effect compression of the air by theforce on it of the piston in the casing 71. The pressure `pressed air,or a liquid, such as oil under pressure.

of the air can be regulated with such a construction to balance theweight of the panel feed and squaring mechaanism. Alternatively, aplunger in the casing may engage a compression type spring above it, ora combination of air and spring pressures could be utilized.

In order that there be as little delay as possible between the feedingof the last panel in a stack and the eecing of the tirst panel in thenext stack, it is desirable to have a stack of panels supplied to alocation adjacent to the feeder before all the panels have been fed fromthe next previous stack. Such a fresh stack to be fed is shown at theright of FIGURE 16 and in the background of FIGURE l, which can bedelivered by suitable conveying means to the location illustrated. Thispanel stack should not be permitted to move into registry with theelevator until it is in the position shown in FIGURES 1 and 16. It isdesirable, therefore, to hold the stack in the position shown in FIGURESl and 16 until the elevator has descended fully.

The new stack of panels may be delivered to the position shown in FIGUREl or 16 by a gravity conveyor, or by an impositive surface frictionconveyor, as may be desired. To insure that the stack does not progresscloser to the elevator than the position shown, the idler roll 1', atthe right of FIGURE 16 has brake means which ordinarily holds it againstrotation and thereby deters further movement of the panel stack untilsuch brake means are released and the rolls 1 driven positively. Brakemeans suitable for this purpose are shown generally in FIGURE l and indetail in FIGURE 19, as including a brake housing 8 located at the endof roll 1' on which the brake is eective.

The roll 1 with which the brake mechanism is associated is carried by ashaft ISG journaled in a pillow block 8l. The end of this shaft projectsbeyond the pillow block and through the bore of a stationary mounting 82to which the cylinder 8 is connected by threads 83. Within the cylinderis received an axially slidable collar 4 encircling the end of shaft 8i)and connected to it for conjoint rotation by a key S5.

Between the collar 84 and the end 86 of cylinder v8 remote from the rollI is received a freely slidable piston 37. Fluid under pressure may besupplied to the cylinder between its end 86 and piston `S7 through aconduit S8. Such huid could be either a compressed gas, such as comineither case the pressure of the fluid will force piston S7 to the leftas seen in FIGURE 19, so that it will press collar 34 against the faceof mounting 82. The surfaces of these parts may be of material which,when thus engaged, will have a high coeicient of friction. Shaft 8i)will thus be effectively connected to the stationary mounting S2 andconsequently will be held against rotation.

A principal purpose of the panel feeder described above is to feedindividual panels from a stack in automatic fashion. Consequently, acontrol panel ltlt incorporates suitable relays and controls showndiagrammatically in FIGURE which are coordinated with appropriatelylocated control switches to effect automatically the proper energizationand deenergization of the various components of the feeder. In effectingautomatic operation of the panel feeder, however, it is important thatsuch feed operation be effected properly irrespective of variations inthe height of panel stacks supplied to the feeder and irrespective ofdifferences in height of various portions of such a stack.

A typical use of such a panel feeder is to feed the sheets edgewise oneat a time to a sanding machine. Prior to such a sanding operation,therefore, the panels may be of nonuniform thickness and, if one end ofeach panel is thicker than the other and all of the thicker ends are inoverlying registry and all of the thinner ends are in overlyingregistry, the height of one end of the stack may be appreciably morethan the yheight of the other end of the stack. Under such circumstancesit is not at all certain that the panel feed bars 35 shown in FIGURE l,for example, would properly engage the edge of the uppermost panel,unless the top of the panel stack were leveled so that the uppermostpanel would be parallel to the chains 34. Mechanism for effecting suchoperation is shown best in FIGURES 20 and 21.

Each of the chains 28 connected to the elevator drive cylinder 24 isshown as lbeing looped around a sprocket 9 at one end and a sprocket atthe other end. One of these sprockets 9 is keyed to the shaft 91carrying one of the gears 29, and the other sprocket 9 is keyed to theshaft 92 at the opposite end of the superstructure. The sprockets 9,therefore, are the driving elements for the shafts 91 and 92, and thesprockets 90 are merely idler or guide sprockets. lf the chains 28 wereixedly connected to the cylinder 24 of the elevator `drive mechanism, itwill be evident that all of the chains 2 would be driven equally throughthe shafts 23 so that all portions of the elevator 17 would be raisedequally. In order to compensate for possible differences in height ofopposite ends ofthe stack, therefore, mechanism is provided to move thechains 2 at one end of the elevator relative to the chains at theopposite end for the purpose of tilting the elevator 17 to some extent.

While the opposite ends of one chain 28 are secured directly to theopposite heads of cylinder 24, the ends of the other chain may beconnected to the opposite ends of a rod 93 adjustable lengthwise of thiscylinder. Such rod is slidable through apertures 94 in the oppositecylinder heads of cylinder 24. In order that cylinder 24 may beeffective to move the chain 2S in which rod 93 is connected, a thrustconnection must be provided between such rod and the cylinder 24.Movement of rod 93 and its chain driving the chains Z at one end of theelevator 17 relative to the other chain ZS and the chains 2 at theopposite end of the elevator I7 may be eiected by making the thrustconnection Ibetween the rod 93 and the cylinder 24 adjustable.

The adjustable thrust connection between rod 93 and cylinder 24 includesa small auxiliary cylinder 95 mounted directly on one of the heads ofthe cylinder 24. The rod 93 extends through this cylinder and has xed toit a piston 96 fitted reciprocably in the cylinder 95 as shown in FIGURE2l. The length of the stroke of piston 96 in cylinder 95 determines theamount of relative movement which can =be effected between the twochains 28, consequently between the chains 2 at the opposite ends of theelevator 17 and therefore the amount of tilt of which the elevator iscapable for the purpose of leveling the uppermost panel of a stack.

Movement of piston relative to cylinder 95 is effected by supply offluid under pressure, such as oil, to one end or the other of thecylinder through connections 97 and 98, respectively. It is preferredthat the relationship of chains 28 be established so that when ythepiston 96 is located centrally of the ycylinder 95 as shown in FIG- UREl the elevator platform I7 will be level. By supplying fluid underpressure through connection 97, therefore, to the left end of cylinder95, as seen in FIGURES 20 and 21, the piston 96 will be moved to theright in such cylinder, so that the chains 2 at the right end of theelevator 17 as seen in FIGURES 1 and 20 will be raised to lift thecorresponding end of the elevator. On the contrary, if fluid underpressure is supplied through connection 98 to the right end of cylinder95, the piston 96 will be moved to the left, as seen in FIGURES Z0 and2l, so that the chains 2 carrying the right end of the elevator 17 asseen in FIGURES 1 and 20 will be lowered, correspondingly lowering thatend of the elevator.

It is preferred that supply of pressure fluid to one or the other ofconnections 97 and 98 be controlled automatically to effect aself-leveling operation of the top panel on a stack when the elevatorhas raised such panel substantially into edge-feeding position. To eectcontrol in this manner, control elements 99 and 9% are locatedrespectively at opposite ends of the panel superstructure which may becarried by a bar 31. Sensing element "9 may control supply of fluidunder pressure to conduit 97 to effect raising of the right end of theelevator 17 so that the corresponding end of the uppermost panel willengage sensing element 99. Conversely, sensing element 55'?" may controlthe supply of uid under pressure to connection 98 so that, if thissensing element is engaged first by the top panel of a stack, rod 93will be shifted by movement of piston 96 to lower the right end of theelevator 17 until the left end of the top panel engages the sensingelement 55g.

The location, function and operation of the various components of theautomatic control mechanism can be correlated best in connection with adescription of the feeder operation. 1t will be understood that variousfeatures of the electrical control mechanism may be varied in providingmechanism to produce a desired automatic operation of the apparatus. Theelectrical control mechanism will be operated by a power supply 101which may have a voltage higher than necessary for the operation of thecontrol mechanism. Such power supply is controlled by ya master switch102 and the voltage is reduced to the desired value by a transformer103. Preferably the output side of the transformer is 110 volts and oneor both of the legs of this circuit may incorporate fuses 104.

Assuming that the elevator has been emptied and has just descended toits lowerrnost position shown in FIG- URE l, the elevator frame willhave engaged and closed normally open switch 105. It is assumed furtherthat an automatic operation of the feeder is desired so that `the switch1116 is in the position shown in FlGURE 22 in engagement with theautomatic operation terminal 107, as distinguished from the manualoperation terminal 108. Closing of the switch 105 effects energizationof relay 109 controlling operation of the roll motor 110, which drivesthe rolls 1 and 11, and energization of the solenoid 1121 which closesthe normally open valve 11-2, preventing access of air under pressurethrough conduit 88 to the brake cylinder 8, thus releasing the brake ofroll 1'.

As soon as the brake is released the action of gravity will move the newstack of panels shown in FIGURES l and 16, causing roll 1 to turn.Alternatively, the stack may be thus moved by an impositive conveyor onthe feed side of roll 1. When the leading edge of the stack of panelsreaches the first roll 1, the stack will be moved on toward the elevatorbecause such rolls will be kept moving by continued energization of themotor 110 through relay 109, still energized by the elevator holdingswitch 105 closed. To this time closed switch 105 has also maintainedsolenoid 111 energized to keep brake -8 released by holding valve `112closed.

Shortly after the trailing edge of the stack of panels is moved olf roll1', the leading edge of the stack will engage normally closed switch 113and open it. Since this switch is in series with switch 105 in thecircuit of solenoid 111, such opening of switch 113 will reenergizesolenoid 111, releasing valve 112 to move to its normally open positionso that again air under pressure is admitted to the brake mechanism. Thebrake will thus be applied to roll 1 so that it will hold the next stackS of panels out of contact with the first roll 1 until the brake isreleased again. As the elevator is raised, switch 105 will be releasedto break the circuit to solenoid 111 before the stack of panels israised off switch 113, allowing it to open again. The brake releasingsolenoid 111 thus remains denergized to keep the brake applied until theelevator descends again with no panels on it.

When the stack of panels S has been moved by continued rotation of rolls1 and 11 into a position above the elevator 17, the leading edge of thestack of panels will engage the arm of the double-pole switch 115 andmove it from the position shown in `F1GURE 20 to break the circuit ofrelay 109 into engagement with its other cons osavea tact to initiateupward movement of the elevator. If the stack of panels is not in justthe position desired, switch 106 may be moved to engage contact 108,whereupon by closing and holding switch 116 the panel stack may be movedstill farther, or by closing switch 117 the motor driving rolls 1 and 11may be reversed to withdraw the panel stack outward somewhat. For safetypurposes an overload circuit breaker 113 may be incorporated in thecircuit of roll motor 110.

Whether under automatic operation the switch 115 is moved to deenergizerelay m9, or the switch 106 is swung from its automatic position to itshand-operated position and switches 116 and 117 are released after thestack S has been placed as desired, the final effect will be to locatethe stack of panels over the elevator 16 with the rolls 11 stopped sothat the panel stack will stay in such position. Thereafter, theelevator 16 will be raised to lift the stack of panels from the rolls11, and again the elevator may be controlled either automatically byplacing switch 119 in engagement with contact 120, as shown in FIGURE20, or manually by moving such switch into engagement with Contact 121.

lf the operation is to be of automatic character, switch 115 engagedwith its left contact in FiGURE 22 by the stack of panels engaged withit, opposite to its normal position, will energize relay 1,22 to effectenergization of the solenoid of solenoid valve 123, which will openconduit 2.7 for supplying fluid under pressure to the right. end ofcylinder 24, as seen in FIGURES l and 20, while venting the conduit 26.Even though switch 115 should be closed only momentarily, relay 122 willremain energized through its holding circuit so that the upward movementof the elevator will be continued until the upper panel of the stack Sengages and lifts the sensing element 124. Upward movement of suchsensing elements will effect opening of switch 125, normally closed, tointerrupt the circuit through the solenoid valve 123. Relay 122 will,however, remain energized, even when switch 125 is opened.

As the sensing element 124 is moved upward, not only is upward movementof the elevator interrupted by opening of switch 125, but the sensingelement also closes switch 126 to energize relay .127. Energization ofsuch relay initiates operation of motor 128 which drives the chains 34carrying lthe feed bars 35 engageable with the end of the top sheet onthe stack S to be fed from the feeder. Relay 127 also is provided with aholding circuit so that this relay will continue to be energized evenafter switch 126 is opened. Motor 128 may be an electrically controlledfluid motor.

A further action effected by raising of the sensing element 124 by thetop sheet of the stach is the closing of switch 130 which initiates thesquaring operation effected by movement of the squaring arms 4 and 41.The three operations of termination of the elevator raising movement byopening of switch 125, starting of the feed motor by closing of switchV126, and initiation of lthe squaring arm movement by closing of switch136 all occur substantially simultaneously.

Closing of switch 130 to initiate the squaring arm movement will alwaysenergize the sclenoids of valves 1311 and 132 controlling the flow offluid under pressure to the left ends of the starboard and port smallercylinders 57 through conduits 57". ln addition, closing of this switchwill admit fluid under pressure to one end or the other of the largesquaring arm operating cylinders depending upon the particular type ofdesired squaring operation selected in advance by the operator.

In order to select the type of squaring operation desired, la selectorswitch 133 is provided which can be set to engage any one of thecontacts 134, 135, 136 and 137. If, `as shown in FIGURE 2G, the switcharm 153 is in contact with switch point 134 when the squaring switch 130is closed, relay 138 will be energized, which in turn will energize thesolenoid of valve 139. This valve normally would -be in a position suchthat fluid under pressure would be supplied to the right end of thelarge port cylinder 55 so as to hold its piston 56 fully to the left asseen in FIGURES 2 and 3. Upon energization of this solenoid, however,the valve would be moved to supply fluid under pressure through conduit55 to -the left Iend of the large port cylinder, so that the piston 56would be moved to the right in the manner shown in FIGURES 2 and 3 untilthe end of squaring rod 54 engages its stop hook 66 as shown in FIGURE5. The solenoid of the other valve 14) would remain deenergized so thatits valve would continue to supply uid under pressure to the right endof the large starboard cylinder 55.

Because only the small starboard piston 58 has moved, the squaring arms4 will -always be shifted to locate the plates 4i) in a predeterminedposition, as shown in FIG- URES 2 and 3, irrespective of the degree ofmovement of the large port piston 56 alone, or, in addition, themovement of the small port piston. Whatever the Width of the panel beingsquared, therefore, plates 42 on squaring arms 41 will shift the paneluntil its opposite edge is engaged with the plates 40 to locate suchopposite edge relative to the machine to which the panel is fed.

If the switch arm 133 were in contact with the switch point 135, relay141 would be energized, which would effect energization of the solenoidsof both valves 139 and 140, so that -air under pressure would besupplied to the left ends of both large cylinders 55 through theconduits 55'. With such setting of the valves both large pistons wouldmove to the right ias shown in FIGURES 7, 9, 1l, 13, 14 and l5, untiltheir respective rods 51 and 54 had engaged their respective stop hooks66 and 67. In each instance, therefore, the panel to be fed would besquared in a central position.

lf the selector switch 133 were placed in contact with the switch point136, closing of squaring switch 130 would energize relay 142. Suchenergization would cause energization of the solenoid of only valve141), so that, opposite to the illustration of FIGURES 6, 8, and l2, airunder pressure would be admitted to the left `end of only the starboardcylinder 55, causing its piston 56 to move while the piston 56 of theport large cylinder would be held to the extreme left end of itscylinder. Consequently, upon each feeding operation the top panel wouldbe squared in an oiset position, always ltoward the starboard side ofthe feeder. Irrespectve of the width of the panel being fed, thelocation of the starboard edge will always Ibe the same, established bythe location of plates 42.

1f the selector switch arm 133 is in engagement with switch point 137,closing of switch 130 will energize one or the other of relays 143 and144, depending upon the rotative position of stepping switch wheel 145.Each time the switch 130 is closed when the selector switch arm is insuch position, the solenoid 146 of such stepping switch wheel will beenergized to reciprocate the ratchet arm 147 to turn the switch wheel145 one tooth. Current is supplied by a lead 148 -to the center of thiswheel, which carries the distributor strip 149. When in the positionshown in FIGURE 20, the strip 149 would energize the brush 150 fortransmitting current to relay 143. The next time that switch 130 isclosed when switch a-rm 133 is in engagement with switch point 137 theratchet mechanism 146, 147 would turn the switch wheel 145 through aquarter-turn, so that the strip 149 would be engaged by the brush 151,which is connected to relay 144. Immediately, therefore, this relaywould be energized to swing the relay contact arm 2 ltoward :the coil ofrelay 144.

The switch point yadjacent to relay coil 143, which is engaged by therelay switch arm 152, is connected to the solenoid of valve 139controlling the supply of fluid under pressure for shifting the largeport piston 56 to the right as seen in FIGURES 2 and 3. The switch pointadjacent to relay coil 144 engageable by relay switch larm 152, on thecontrary, is in circuit with the solenoid of valve 140, which controlsthe supply of fluid under pressure to move large piston 56 of thestarboard cylinder tto the right. It will be evident, therefore, thatlas long as selector switch arm 133 is in engagement with switch point137 the rotary switch will energize brush 150 and relay 143 in oneinstance and brush 151 and relay 144 in the other instance, alternately.Switch arm 152 by such relay energization will be swung from itsposition to energize the solenoid of valve 139 to its position toenergize the solenoid of valve 1419 and back again alternately.

With the stops 66 and 67 for the squaiing rods 54 and 51, respectively,set in one of the positions shown in FIG- URES S, l0 and l2, forexample, it will be evident that one squaring rod will engage its stopand then the other squ'aring rod will engage its stop in alternateoperations. Consequently, panels fed by the feeding apparatus will besquared in offset positions, one sheet being onset to one side, and thenext sheet being offset in the opposite side, Aalternately in successiveoperations. In each instance, of course, with whatever switch terminalthe switch arm may be engaged, closing of squaring switch 130 will causethe solenoids of both valves 131 4and 132 controlling supply of fluid toboth smaller cylinders 57 to be operated for supplying uid underpressure -to the left ends of such cylinders. The pistons 53 will notalways move in their cylinders, however, for the reasons discussed inconnection with the operation of the mechanism as portrayed in FIGURES8, l0 and l2.

The squaring arms 4 and 41 will remain in their inward squan'ngpositions throughout the operation of feeding the top panel from thestack, because the top panel being fed will hold the sensing member 124in its upper position until after the panel has been fed out from undersuch sensing member, as shown in FIGURE 17. As the sensing member dropsdownward, the switch 130 will open, which will deenergize all :of thesolenoids of valves 131, 132, 139 and 140, which may have beenenergized, causing all the valves to be positioned for supplying `ailunder pressure to the right ends of both lthe large cylinders 55 and`the srnall cylinders 57. Consequently, both pistons 56 and both pistons58 will be held fully to the left in their positions shown in FIGURE 4.The squaring arms will thereby be shifted outward to their position ofgreatest spacing.

Considerably before the panel reaches its position shown in FIGURE 17the panel P will have been gripped by the machine to which it is beingfed so that it will be puhed the remainder of the distance off the stackof panels S without reliance upon the pushing action of a feed bar 35.In fact, if the feed bar continued to be engaged with the panel endduring its movement by chains 34 around the arcs of sprockets 33adjacent to the discharge end of the feeding mechanism, the bar 35 wouldscrape transversely of the panel edge, which might deface such edge orcatch and tend to raise the trailing edge of the panel, which would beundesirable. Consequently, control mechanism is provided forinterrupting the operation of the feed motor 128 brieliy when thefeeding bar 35 approaches the sprockets 33 adjacent to the discharge endof the feeding apparatus to enable the panel pulling mechanism to movethe panels trailing edge out of proximity to the bar 35, so that nocontact of the bar with the panel can occur as such bar is moved upwardaround the sprockets 33 adjacent to the discharge end of the apparatusby the chains 34.

The control mechanism provided to interrupt operation f= of feed motor128 briey for the purpose discussed includes the switch 153, which wouldbe located conveniently to be closed by movement of a bar 35. Closing ofsuch switch will energize relay 154 to attract simulta neously itsswitch arms 155 and 156. Such movement of switch arm -155 immediatelywill break the circuit to the feed motor 12S so that it will stop butwithout deenergizing the principal control relay 127 for ythis motor,which will remain energized because of its holding circuit. Thesimultaneous movement of switch arm 156 will effect immediatedeenergization of relay 154 so that the switch arms 155 and 156 willtend `to return to their relaydeenergizized positions. Associated withthe switch arm 155, however, is a dashpot 157 which will delay reclosingof this switch sumciently so that the panel P may be removed to withdrawits trailing edge out of the upwardly moving path of the pusher bar 35.

When switch arm 155 recloses following deenergization of relay 154, thefeed motor 128 will be reenergized immediately because of the continuedenergization of relay 127. Despite the fact that switch 153 remainsclosed until after the chains 34 have been moved through an appreciabledistance after switch 155 has again closed, relay 154 will not bereenergized immediately because its switch arm 156 in its circuit isalso provided with a dashpot 158. This dashpot is shown as being longeror in some way slower acting than dashpot 157, so that reclosing ofswitch 156 will be delayed until switch 155 has reclosed and the chains34 have been moved far enough to enable switch 153 to open. Relay 154will therefore not be reenergized until switch 153 has been closedagain, which will be on the next panel feeding cycle.

When thus reenergized by reclosing of switch 155, the feed motor 128will continue to operate until the pusher bars have almost reachedpositions at the extreme ends of the paths of chains 34. At this timethe pusher bars or chains will move switch 159 to open position, whichwill break the circuit of motor 12S and the holding circuit of relay 127so that both will be deenergized. The chains 34 will therefore stopafter coasting sufiiciently to place the pusher bars 35 approximately intheir extreme positions shown in FIGURE 17.

It will be appraciated that the panel P may have moved to the positionshown in FIGURE 17 so that the sensing member 124 has dropped onto thetop of the next panel P in the stack S before the chains 34 havecompleted their movement into the position'shown in that gure.Nevertheless, because of the holding circuit of relay 127, such feedingoperation will be completed even though switch 126 has been released andhas been moved to open position by dropping of the sensing member. Also,because of the downward movement of the sensing member, the squaringAarm control switch 130 may have opened to deenergize the solenoids ofthe various valves 131, 132, 139 and 140 to eect retraction of thesquaring arms into the position shown in -FiGURE 16. 1n that eventswitch 125 also will have been released to close, which, because of thecontinued energization of relay 122 through its holding circuit, wouldtend to reenergize the solenoid of valve 123 and cause the elevator 16to be moved upward by supplying fluid under pressure to the right end ofcylinder 24 through conduit 27.

Despite the closing of switch 125, however, upward movement of theelevator will not occur until after the chains 34 have completed theirmovement to -their initial positions with the cross bars 35 at theextreme ends as shown in FiGURE 17. By this time, of course, switch 1313will have been released so that the squaring arms have been retracted.Such sequence of operation is insured by the provision of switch arm1611 under the control of relay 127. This switch, which is normallyclosed, is in series with switch 125 under the control of the sensingelement 124 and cannot return to closed position until relay 127 hasbeen deenergized, which is effected by opening of switch 159.Consequently, even though switch 125 has been closed, relay 127 musthave been deenergized at the completion of travel of chains 34 beforeupward movement of the elevator is resumed. As soon as the elevator hasmoved upward the thickness of one saves panel, switch 125 will be openedagain to interrupt its movement, and switch 126 will'have been closedagain to energize relay 127 and open switch 161i, so that the next feedoperation of chains 34 will be initiated and the elevator again willremain quiescent until the conclusion of such feed chain cycle.

It is possible that some unusual circumstance may iti occur, so that thesensing element 124- is not raised as the elevator moves upward to openlswitch 125 and close switch 126 to open switch 160. In that case theelevator would continue to move upward and cause damage to the machineif a safety switch were not provided. Thus, for example, a stick mightbe incorporated in a stack of panels which would engage between theupper panel and a chain 34 or bar 31 to raise the feeding mechanismsupported on arms 30 without the sensing element being lifted relativeto such arms. For such event an upper safety limit switch 161 isprovided which would be actuated by excessive swinging movement of anarm 31) or excessive upward movement of a bar 31, for example. Suchsafety switch is arranged in circuit with both elevator raising solenoid123 and elevator lowering solenoid 162. As long as switch 161 is inengagement with its contact 163 and switch 125 is closed, solenoid 123will remain energized to continue upward movement of the elevator. Uponactuation of switch 161 to disengage its terminal 163 and engage itsterminal 163', however, the circuit to solenoid 123 would be broken andinstead a circuit would be completed to the elevator lowering valvesolenoit 162 controlling supply of liquid under pressure to conduit 26supplying the left end of cylinder 24, as seen in FIGURE 1. At the sametime supply of uid under pressure to conduit 27 would be discontinued.Consequently, the elevator immediately would move down and such downwardmovement would continue until switch 161 had been released, whereupon itwould be reengaged wtih its terminal 163. If the diiculty had beenremedied by that time, switch would be actuated to terminate the upwardmovement of the elevator, but otherwise if the elevator were raisedsufficiently again to move switch 161 out of contact with its `terminal163 and into contact with its terminal 163', the upward movement of theelevator again would be arrested by the actuation of this switch, and itwould be moved downward. Such short up and down hunting movement of theelevator would continue until the cause of such upward overtravel of theelevator had been removed.

When operating normally switch 125- would be closed and openedalternately to effect raising movement of the elevator 16 by incrementsequal to the thickness of panels on the stack S until the last panel hadbeen fed from the elevator. At that time, instead of the sensing element12e being supported in the intermediate position shown in FlGURE 17 bythe next panel tol be fed, it would have dropped downward into theposition shown in FIGURE l to close switch 164. Closing of such switchenergizes relay 165i, which breaks the holding circuit of elevatorraising relay 122 and, by closing switch 166, energizes the solenoid`162 of the elevator lowering valve to supply fluid under pressure toconduit 26, while interrupting supply of such fluid to conduit 27. Suchsupply of fluid will eifect movement of cylinder 24 to the left, whichdrives chains 2 to lower the elevator 16, 17 into the position shown inFIGURE 1. When the elevator reaches this position, normally closedswitch 167 will be opened to deenergize relay 165 for interruptingdownward movement of the elevator.

As also explained previously, assuming that another stack of panels S isin the position shown in FIGURES 1 and 16 to be fed to the elevator, theclosing of switch 165 would have initiated movement of such stack ofpanels toward the elevator. In the absence of interference by theoperator such stack of panels will be fed automatically to the elevator,whereupon the elevator automatically will be raised until the top panelof the new stack again reaches the feeding position. Thereupon automaticfeeding of the panels from that stack will be effected in the mannerdescribed.

In some instances it may be desirable to lower the elevator before allthe panels have been fed from the stack on it. Alternatively it may bedesired to raise or lower the elevator at will for some reason. For thatpurpose switch 119 may be swung from engagement with switch point 120into engagement with switch point 121, and when it is in the latterposition the elevator control relays 122 and 165 cannot be energized.The solenoid of valve 23 can, however, be energized at will to eiectraising of the `elevator by closing of manual switch 16S. Preferablythis switch is of the momentary contact type, so that as soon as theoperators hand is removed from it it will open automatically andterminate upward movement of the elevator. Conversely, the elevator maybe moved down at will be closing of manual switch 169 to energize thesolenoid valve 162. Again, this switch should be of the momentarycontact type, so that as soon as it is released by `the operator it willopen.

In case of emergency, of course, the master switch 102 can be pulled,whereupon all of the drive mechanisms will be deenergized and movementof all parts of the feeder will stop.

As has been discussed previously, it may be desirable to incorporate inthe mechanism an arrangement to modify the action of the main elevatorhoisting drive by tilting the elevator somewhat -to compensate fordifference in thickness of a stack of panels at its opposite ends. Theauxiliary adjusting mechanism to move relatively the chains 2 atopposite ends of the elevator has been described mechanically inconnection with FIGURES 20 and 21. The sensing elements 99 and 99' atopposite ends of the elevator, which would be engaged by the oppositeends of the top panel on a stack, are arranged to control respectivelyswitches 17 t) and 171. These switches can energize respectivelysolenoids 172 and 173 of valves to control the supply of iluid underpressure to conduits 97 and 98 connected to the left and right ends,respectively, of auxiliary cylinder 95.

As the elevator is raised, if switch 170 is engaged rst, indicating thatthe left `end of the stack of panels as seen in FIGURE 2O is higher,liquid would be supplied to the conduit 97 by the valve actuated byenergiz-ation of solenoid 172 corresponding to switch 170. The valvecontrolled by solenoid 173, which -is not energized, would be positionedto connect conduit 98 communicating with the right end of cylinder 95 toa hydraulic liquid return conduit. Consequently, the piston 96 wouldmove to the right, as seen in FIGURES 20 and 2l, to raise the right endof the elevator more than the left end. As soon as the right end of thetop panel engaged the sensing parallelogram 99' to move switch 171, itsnormally closed upper contact would be broken, thereby deenefrgizing thevalve controlled by solenoid 172 so that no more pressure uid would besupplied through conduit 97 to the left end of cylinder 95. Whilemovement of the switch arm into engagement with the opposite contactwould seek to energize solenoid 173 for supplying iiuid under pressureto the right end of auxiliary cylinder 95, such solenoid ywould not beenergized because its circuit would be broken by switch 170. This switchalso has a contact which would be closed in the circuit of solenoid 173when the sensing parallelogram 99 is not engaged by the top panel of astack. With both of the sensing parallelograms 99 and 99' engaged,however, both solenoids 172 and 173 would be deenergized so that thepiston 96 would not be shifted additionally in its cylinder 95.

Piston 96 would therefore remain stationary relative to its cylinder 95,despite continued movement of cylinder 24 relative to the stationary rod25 until the stack of panels had been raised sufliciently to open eitherswitch 125 or to move switch 161 out of engagement with its contact 163.In either event solenoid 123 would be deenergized to cut olf the supplyof uid under pressure to cylinder 24 so that upward movement of theelevator would be terminated. While the movement of piston 9'6 in itscylinder 95, normally will occur during continued up ward movement ofthe elevator eiected by the cylinder 2.4, it is important that theleveling adjustment effected by piston 96, as well as the upwardmovement of the elevator,

18 be interrupted if movement of the feed bars 35 should begin. Thecurrent supply to the solenoids 172 and 173, therefore, like that to thesolenoid 123 controlling the upward movement of the elevator effected bycylinder 24, is through the switch 166 of relay 127. If this relayshould be energized to open this switch, the circuit including solenoids172 and 173 would be deenergized simultaneously.

As has been described previously, the next operation is for the feedmechanism to slide off the stack the top panel, which has been squaredand shifted, if necessary, into proper alignment with the predeterminedfeed path. Pressure uid is not admitted again to either conduit 97 or98, however, to shift piston 96 relative to its cylinder until solenoid123 has again been energized to index the elevator upward a distanceequal to the thickness of the new top panel on the stack. Thereupon oneor the other of switches and 171 Will be moved first, and then bothtogether, as may be required to level the new top panel.

While, because of cumulative variation in thickness of the panels in astack, the movement of piston 96 relative to cylinder 95 might beconsiderable when the switches 170 and 171 are actuated by the rst toppanel of a new stack, the piston 96 by actuation of such switches willbe returned gradually toward its central position in cylinder 95 byincrements as the height of the panel stack decreases because successivepanels are removed from it. When the last panel in the stack is leveledby movement of piston 96 relative to cylinder 9S, therefore, the pistonwill be approximately in its central position, so that the elevator willbe sufliciently level to receive the next stack of panels when it hasdescended to its bottom position. The arms 99 and 99 of the parallellinkage sensing devices will be long enough so as to be engaged by theopposite ends of the top panel of a stack in each instance whether suchpanel be long or short within the range of panel lengths intended to befed by the sheet feeder.

In the modification shown in FIGURES 23 to 26, inclusive, the lowerportion of the sheet feeder will be similar to that shown in lFIGURES land 16 as described above. The frame will include the posts or columns14 and the upper horizontal frame members 15 connecting the upper endsof posts at opposite ends of the machine. A load of sheets to be fedwill be loaded upon the platform 17 as previously described and will beraised by suitable hoist mechanism, as discussed, into a position forfeeding the sheets edgewise one at a time from the top of the stack. Thesensing element 124 will be engaged by the upper sheet of the stack asit is lifted by platform 17 when such upper sheet approaches the edgefeeding elevation, and lifting of such sensing member by upward movementof the stack will initiate operation of the edge feeding mechanism.

The principal diiference in the machine shown in FIG- URES 23 t0 26,inclusive, is the type of edge feeding mechanism utilized. Instead ofeffecting edgewise movement of the top sheet by a pusher bar engagingthe trailing end of the sheet, the feeder mechanism of FIGURES 23 to 26,inclusive, has mechanism to grip the edges of the sheet extendingparallel to the direction in which the sheet is to be fed and suchmechanism is then moved bodily in the feed direction simultaneously tomove the sheet in the direction of feed. With such mechanism, it isimmaterial how long in the direction of feed movement the sheets may beor what their positions lengthwise of the feed direction may be withinwide limits. It is even entirely practical to feed sheets of randomlength piled in a single stack as long as the sheets in such stack areall of the same width and are stacked widthwise in registry and withtheir leading ends also approximately in registry. With this type ofedgewise feeding mechanism, as well as with that previously described,the sheets may be fed in centered position, in oiset position oralternately in oppositely offset positions as previously described.

spaar/'es The primary mechanism for actuating the sheet edge engagingmembers includes the racks 4 and 41 which are driven by the drive rods51 and 54 actuated by the pistons in cylinders 55, as has been explainedin detail in connection with FIGURES 5 to l5, inclusive. The type ofsheet movement eifected transversely of its direction of movement willbe established by setting the regulating handle relative to latch plate69. When the sheet on top of the stack of sheets has been located in thedesired position transversely of its length, it is fed lengthwise to theleft as seen in FIGURES 23, 24 and 25.

The previously described type of mechanism was designed to push thesheet through a distance at least nearly equal to its length, whereasthe mechanism of FIGURES 23 to 26, inclusive, need only move the sheetendwise suniciently so that its leading end will be engaged between andgripped by the pinch rolls 180 and 181. From that position the sheetwill be moved lengthwise over the remainder of its length, whatever thatmay be, by rotation of such pinch rolls. The upper roll 181 is drivenfor that purpose by a belt 182 and motor 183.

'While it is preferred that the pinch rolls 180 and 181, or at least oneof them, have a resilient surface so as to grip the sheet firmly andaccommodate sheets varying in thickness to some extent, it is preferredthat the spacing of the roll axes be adjustable to accommodatesheets ofconsiderably different thicknesses. While the lower rolls 180 may bemounted to rotate about a stationary axis, the upper roll 181 may besuspended by rods 184 carrying bearings supporting the opposite ends ofthe roll axle respectively. The upper ends of these rods are mounted oncrank pins 185 of crank disks 185 which are mounted on opposite ends ofthe shaft 186. This shaft can be turned by the belt 186 driven by thethickness-adjusting arm 187 which may be secured in any of variousadjusted positions by engaging a spring pin in its handle with anappropriate latch hole in the latch plate 188. Vertical movement of theaxis of roll 181 effected by this adjusting mechanism is assured byproviding blocks 181 on opposite ends of the roll axle which areslidably guided in vertical ways 189.

The mechanism for shifting the top sheet of the stack lengthwise intoengagement with the pinch rolls 180 and 181 is supported on the frame190 which is suspended by plates 191 from rollers 192 which run onstationary tracks 193. These tracks are supported by hangers 194 fromspaced cross beams 195, which, in turn, are suspended by plates 196 fromthe longitudinal beams 15. To assure that the carriage composed of theframe 190 and its associated parts will be held in proper verticalposition as Vit is guided for .reciprocation by the tracks 193 and willnot become derailed, it is preferred that backing rollers 197 alsomounted on plates 191 be provided which will bear upon or at least lieclosely beneath the lower edges of the tracks 193. Engagement of suchrollers with the track bottoms will prevent appreciable upward movementof the sheet clamping carriage.

In order to effect movement of the upper sheet of the stack to the pinchrolls 180 and 181 by reciprocation of the caniage including the frame190 and its associated parts guided by the tracks 193, such carriageincludes sheet edge clamping mechanism. Such clamping mechanism issupported principally by the side bars 200 which are secured to the endsof the racks 4 and 41, respectively, in parallel relationship. Theactual contact with the sheet edges is effected by blocks 201, which aresupported by plates 202 movable vertically relative to the side bars200. Guiding such movement each plate 202 has in it an upright slot 203through which extends the shank of a pin 204 having on it a headengageable with .the face of the plate 202 so as to maintain it inposition close along side the `adjacent side bar 200, The weight ofthersheet edge engaging blocks 201 is supported by chains 205 enablingsuch blocks to move upward but limiting their downward movement.

The upper ends of chains 20S are secured to rods 206 extending alongopposite sides of the reciprocating carriage and secured to the mainframe by bars 207 which may be of angle cross section. The blocks 201are guided for movement transversely of the longitudinal sheet edges anddirection of sheet feed by sliding engagement of such blocks and theirsupporting plates 202 with strips 208 at opposite sides of such plates.The plates are supported from such strips for sliding movement by pins202 slidably engaging the upper sides of such strips. The outer ends ofthese strips will be carried by crosspieces 208 secured to the lowerends of chains 205. The inner ends of these strips have end piecesprojecting upward from them. In such end pieces are slots 209, receivingpins 210 mounted on the frame of the carriage, forming a connectionenabling the inner ends of the strips 20S as well as their outer ends tomove vertically upward from a lower mounting position. As the stack ofsheets is raised, therefore, the upper surface of the upper sheet willalways engage the strips 208 and may lift them to some extent. By suchengagement of the sheet with the strips, proper disposition of the sheetedge engaging blocks 201 with the edge o-f the upper sheet will alwaysbe assured.

The clamping action of the blocks 201 against the opposite edges of theuppermost sheet of the stack is accomplished by relative approachmovement of the side bars 200 backing the plates 202. When theregulating handle of latch plate 69 has been set in accordance with thewidth and location desired of the Sheets to 1be. fed, the initialclamping movement of the blocks 201 will be eiected by bodily movementof the racks 4 and 41 and of the side bars 200 carried by them. Suchinitial clamping movement will involve approach movement of the sidebars 200 so as to space the clamping blocks 201 apart a distanceslightly in excess of the actual width of the sheet to be fed. Suchmovement may `also involve shifting the sheet on top of the stack bodilyin one direction or the other transversely of the direction of sheetfeed if the sheet is to be fed in an offset direction. Movement of theracks 4 and 41 will not move the clamping blocks 201 together far enoughto clamp'the sheet tightly however.

After the sheet on top of the stack has 'been located in approximatelythe desired Position to be fed by reciprocation of the racks 4 and 41,the side bars 200 are moved toward each other an additional small amountto effect the actual tight 4clamping of the sheet edges by the blocks201. To effect this action, one of the side bars 200 carries atlocations spaced lengthwise of it corresponding to the spacing betweenracks 4 auxiliary clamping actuators 211. These actuators are of thehuidoperated type and are shown as including a cylinder secured to theside bar 200 and a plunger rod 212 secured to a rack bar 4. Theseactuators are preferably of the pneumatic type.

In FIGURE 26, a situation is illustrated in which a stack of panelsnarrower than the maximum width stack is to be fed in a position offsetalways in the samev direction from center feed. Consequently, thisnmower stack has been placed on the elevator 17 in an offset position asindicated by dot-dash lines. The feed control lever will, therefore, beset relative to latch plate 69 so that the pneumatic actuator 211 wouldoccupy approximately the position shown in dot-dash lines when the rackshave been moved into feed position. Whether the racks have positionedthe actuators 211, as shown in full lin or in dotdash lines in FIGURE26, the subsequent operation for effecting tight clamping of the sheetedges will be the same. Fluid under pressure supplied to the actuatorswill move themY and the side bar 200 carrying them toward the sheet edgeso as to press the block 201 carried by the plate 202 backed by the sidebar tightly against the sheet edge. Such action will also insure thatthe sheet will be pressed tightly against the clamping blocks 201 21backed by the opposite side bar 200. As thus firmly gripped between theclamping blocks 201 the sheet will be shifted lengthwise with thecarriage composed of frame 190 and its associated parts as it is movedin the direction of sheet movement.

The mechanism for effecting reciprocation of the carriage along thetracks 193 reacts between the frame structure and a plate 198 securely-anchored to the central portion of the frame 190. The actuator 213 foreffecting reciprocation of the carriage is of the fluid pressurepiston-and-cylinder type vand preferably is pneumatic. One end of suchactuator is connected by mounting arms 214 to a cross beam 194 and theopposite end of the actuator is pivotally connected to the thrust plate19S by a yoke 215. As uid under pressure is supplied to the actuator toextend it, a thrust will be exerted toward the left, as seen in FIGURE23, to move the carriage and the top sheet of the stack clamped by theblocks 261 to advance the sheet to the left into engagement with thepinch rolls 18|) and 181. Upon release `of the sheet by retraction ofthe pinching actuators 211, the sheet may then be fed on to the left byrotation ofthe pinch rolls.

To regulate the operation of the feed mechanism to handle sheets ofvarying thickness, the sensing member 124 can be adjusted vertically.For ythis purpose, such sensing member is mounted slidably in the lowerend of rack 220. A shaft 221 carries a pinion 222 meshing with suchrack. The shaft 221 may be turned by swinging a handle 223 secured to itfor the purpose of raising and lowering the rack 220 by rotation of thepinion 222. When the sensing member 124 has thus been raised or loweredto the desired position, the handle may be secured in position by aspring-pressed pin engaging in a hole of latch plate 224.

The stroke of the carriage for feeding the sheet lengthwise can beterminated automatically at opposite ends of the carriage stroke. Forthis purpose, a limit switch 22S is mounted on a cross beam 19S of themachine frame to be engaged by adjustable stops 226 and 227 which aremounted on the carriage frame 19t). When the actuator 213 is energizedto eiect a feeding movement of the carriage, the stop 226 will be movedby the carriage until it engages the arm of limit switch 225 in themanner shown in FIGURE 25. Such engagement may effect automaticallyreversal of flow of fluid under pressure to the actuator 213 so that thecarriage travel will be reversed and, when the return stroke has beencompleted, the stop 227 will engage the limit switch 225 to terminatereturn movement of the carriage. It will be understood, of course, thatactuation of the limit switch 225' by engagement of stop 226 with itshould also effect operation of the sheet-clamping actuators 221 torelease the sheet before the return movement of the carriage isinitiated. The stops can be adjusted to establish precisely the positionof the carriage at opposite ends of the stroke.

In order to provide steady movement of the sheet in flat condition bythe pinch rolls 180 and 181, a hold-down plate 230 may be used at thedischarge side of the pinch rolls. This plate is mounted on the swingingend of the forwardly and downwardly inclined arm 231 which is pivotallysupported on shaft 232, as shown in FIGURE 23.

I claim as my invention:

l. Panel-positioning mechanism comprising two panel edge-engagingmembers disposed in spaced relationship for engaging opposite edges,respectively, of panels to be positioned, means mounting each of saidmembers for movement toward the other, two fluid pressure actuatingmeans operatively connected, respectively, to said panel edge-engagingmembers, each of said fluid pressure actuating means including a firstpiston-and-cylinder actuator, a second piston-and-cylinder actuatormounted for movement by said iirst piston-and-cy-linder actuator, and amember connected to its corresponding panel edge-engaging member andmovable by both of said first and second actuators, in an amountcorresponding to the combined movement thereof, means operable to supplyfluid under pressure to said actuators, and control means for said uidsupply means operable to effect supply of fluid thereby simultaneouslyto the second actuator of each of said actuating means and to the firstactuator of only one of said actuating means for moving saidpanel-engaging members to position a panel.

2. Panel-positioning mechanism comprising two panel edge-engagingmembers disposed in spaced relationship for engaging opposite edges,respectively, of panels to be positioned, means mounting each of saidmembers for movement toward the other, two fluid pressure actuatingmeans operatively connected, respectively, to said panel edge-engagingmembers, each of said fluid pressure actuating means including a firstpiston-and-cylinder actuator, a second piston-andcylinder actuator movedby said first piston-and-cylinder actuator, and a member connected toits corresponding panel edge engaging member and movable by both of saidrst and second actuators, in an amount corresponding to the combinedmovement thereof, and means operable to supply tiuid under pressuresimultaneously to the second actuator of each of said actuating meansand in alternate sequence first to one and then to the other of thefirst actuators of said actuating means for moving said panel-engagingmembers to position alternate panels engaged thereby in alternatepredetermined positions.

3. The panel-positioning mechanism defined in claim 2, and stop meansengageable by the member of each fluid pressure actuating meansconnected to the corresponding panel edge-engaging member and operableto limit movement first of one such member and then of the other suchmember corresponding to the fluid pressure actuating means the rstactuator of which receives fluid under pressure.

4. The panel-positioning mechanism defined in claim 3, and meansoperable to adjust the position of the stop means depending upon thewidth of panels being positioned.

5. Panel-feeding mechanism for feeding panels edgewise one at a timefrom a stack of panels raised by elevator means into a position locatingthe top panel of such stack at a predetermined level, comprising controlmeans for deenergizing the elevator means, squarin g means engageablewith an edge of the top panel of such stack and operable to shift suchpanel edgewise into a predetermined position for feeding, feed meansoperable to engage an edge of the top panel of such stack at suchpredetermined level and shift such panel edgewise off the stack, sensingmeans engageable by the top panel of' such stack moving upward to suchpredetermined level, and means operable automatically by said sensingmeans moved by such top panel to actuate said control means fordeenergizing the elevator means, -to effect operation of said squaringmeans and to initiate operation of said feed means.

6. Panel feeding mechanism comprising supporting means operable tosupport a stack of panels, feed means operable to move the top panel ina given direction off the stack, first means engageable with one edge ofthe top panel of such stack disposed generally parallel to such givendirection, drive means for mov-ing said first means transversely of suchgiven direction to shift such panel transversely to such edge intoalignment with a first predetermined path of movement parallel to suchedge and such given direction, second means engageable with the oppositeedge of the new top panel and movable by said drive means transverselyof such given direction and opposite to such direction of movement ofsaid first means to shift such new top panel transversely of its edgeengaged by said second means in the -direction opposite that vin whichthe first top panel was shifted by said first means and into alignmentwith a second predetermined path of movement parallel to the panel edgeengaged by said second means and spaced lfrom such predetermined path

